1. Field of the Invention
The present invention relates to a clamp device for a hand air pump that has a protective ring to avoid damage to a rubber sealing plug of the clamp device.
2. Description of the Related Art
FIG. 7 of the drawings illustrates a conventional clamp device attached to a hand air pump 1 for holding a valve 90 of an article (e.g., a bicycle tire) to be inflated. The clamp device includes a sleeve 82, a rubber plug 81 mounted in the sleeve 82, a nozzle 83 communicating an interior of the rubber plug 81 with the hand air pump 1, and an end cap 80 that holds the tire valve 90. In use, the sleeve 82 is rotated to be in threading engagement with the valve 90 such that the rubber plug 81 that provides a sealing effect for inflation tends to wear and thus be damaged. The present invention is intended to provide an improved clamp device to solve this problem.